Abstract
Abstract: :
Purpose: To establish a rat model of the optic nerve crush injury by aneurysm clip and to evaluate the optic disk damage in the model by confocal scanning laser ophthalmoscope (cSLO). Methods: The optic nerves of Sprague-Dawley rat were crushed at the site 3mm behind the eyeball for 1 minute using aneurysm clip (110 g) and Sham operations were done in the fellow eyes. After 4 days, 1, 2, and 3 weeks, the retrograde labeling of the retinal ganglion cells (RGCs) was done by the dextran tetramethylrhodamine (n = 6, at each time point). The eyes were enucleated at 24 hours after the retrograde labeling and the labeled RGCs in 12 standard areas of each retina were counted under the fluorescence microscope. The optic disk (n = 6) was analyzed by cSLO at each time point. Results: The numbers of labeled RGCs (cells/mm3) under the fluorescence microscope at 4 days, 1, 2, and 3 weeks were 1082 ± 178 (86.0% of normal RGCs density), 694 ± 83 (55.2% of normal RGCs density), 289 ± 57 (22.9% of normal RGCs density), and 245 ± 52 (19.5% of normal RGCs density). The parameters that represent significant changes were cup volume, mean cup depth, maximum cup depth, and cup shape measure. The number of labeled RGCs and the cSLO parameters began to change significantly at 1 week from those of control eyes and baseline measurements, respectively. Conclusion: Using the aneurysm clip, it was possible to damage the optic nerve quantitatively in our animal model and to evaluate the optic disk change by cSLO.
Keywords: 316 animal model • 498 optic disc • 431 imaging/image analysis: non-clinical